Fibrous osteoma of the jaws

Thirteen cases of fibrous osteomas of the jaws are reported and the pathology of two other recorded cases discussed. The bone was formed by the process of fibrous or membranous ossification, cartilage being seen in a minute trace in only one case. In twelve cases the tumor consisted largely of cancellous bone and fibrous marrow. In three it consisted largely of fibrous tissue in varying degrees of maturation, and ossification was proceeding slowly. There was also myxomatous tissue present in three cases and occasional small islands rich in giant cells in two. Microscopic signs of inflammation were rarely present.